I know a lot of people have old style SAN 210s or have had them so im looking for help on an motor problem...
My driver started the boat yesterday to pull me for my second set and the boat had a very irregular idle (up and down uo and down, almost like a hot rod with a gnarly cam on it) to the point where it shut off and then he re-started it and pulled me , runs fine past idle

Was told maybe the Throttle Positioning Sensor needs replaced, fuel is only 2 weeks old at most and sparkplugs changed regularly. Figure someone has ran into this before...

Check also the alternator. My Sanger V210 did this until I found out I needed a new alternator. When I replace it, this completely stopped. (Something about the alternator not kicking in until 800-1,000 RPM. When it does, the engine revs.)

i would look for a vacume leak. i would think if it was a cap or rotor it would have a miss at any rpms. i would also pull the air filter off and clean the inside of the throttle plate. just use a little carb spray and open the throttle wide open so the flap is out of the way and clean the carbon that usually builds up there. of course do this with the boat not running. that will cause the iac tps to not register right

Another thing I've heard great reviews about is "sea-foam" Probably wont help but wouldnt hurt running a bottle through with a fresh tank of fuel. I've heard great claims from ppl but never experienced any first hand.